Goto your forum settings and then do the following:
Well you first link to the image you want to use.
So select the image you have on your server by clicking image and typing the url in.
E.G -
Quote: "{img}http://www.traynor1987.com/example.jpg{/img}"
you then highlight the whole thing including the {img} and {/img} then click link and type the url you wanted. and you will end up with something like this:
Quote: "{href=http://www.traynor1987.com}{img}http://www.traynor1987.com/example.jpg{/img}{/href}"
That should make the image and make it link to the page you want.
*Change the { and } to [ and ] to make it work
